Did you mean a house to raise butterfly caterpillars in? If you're talking about a house for adult butterflies...well, instead of a butterfly 'house', I'd just include plants in the garden that butterflies like...the nectar plants and the host plants. With the nectar plants, you provide nectar for the adult butterfly. On the host plants, the butterflies might lay eggs, then the caterpillars feed on the host plant until it's ready to pupate. http://www.thebutterflysite.com/life-cycle.shtml
There are lists of plants elsewhere on the forum you posted on.

I would feel more optimistic about a bright future for man if he spent less time proving that he can outwit Nature and more time tasting her sweetness and respecting her seniority. E. B.White
Integrity can never be taken. It can only be given, and I wasn't going to give it up to these people. Gary Mowad

Stephanie.....Dale Clark said in a seminar on what bfs do in winter, basicallly not to waste money on them unless you wanted a decorative wasp nest.
If you want to encourage them, plant host plants they use.